Long-suffering investors in Shaft Sinkers saw shares of the fully listed company that carries out the digging for miners collapsed a further 6.12p or 46 per cent to 7.12p.

They were floated at 124p in December 2010 and flirted with the £2 level six months later, but have been friendless for months.

Sellers were out in force again yesterday after the company said it was seeking an urgent injection of new funds following a further deterioration in its financial position.

Digging for success: Shaft Sinkers shares collapsed

Negotiations have begun over various financing methods as well as the disposal of certain assets and the board is continuing with the objective of preserving value for shareholders while still enabling the company to continue trading.

It has been badly hit by the five-month strike across South Africa’s platinum industry and the cost of a legal dispute with Russian fertiliser group, Eurochem.

In May, it warned that the South African situation put it in an increasingly tight cash position and it had started a series of cash saving measures.

International Mineral Resources, a company owned by a trio of oligarchs – Alexander Machkevitch, Patokh Chodiev and Alijan Ibragimov – sits on a 48 per cent stake in Shaft Sinkers.

They are the very same individuals behind ENRC, the colourful Kazakh mining giant. Their stake in Shaft Sinkers has plummeted from £40million-plus to around £1million.

The Footsie took a further turn for the worse, falling 45.67 points to 6,672.37, while the FTSE 250 lost 109.76 points more to 15,439.87.

Profit-taking gathered pace as sentiment was unsettled by euro news that Banco Espirito Bank, Portugal’s largest listed bank by assets, had missed a debt payment.

Rating agency Moody’s cut its rating on the bank from B2 to Caa2, a level equivalent to a ‘junk bond’ and classified it as ‘extremely speculative’.

As shares and bonds of the Portuguese lender fell, rumours were rife that its parent company, Espirito Sante Int is considering a debt-for-equity swap.

As expected, the Bank of England left UK interest on hold at 0.5 per cent and the size of its monthly stimulus programme at £375billion.

Unchanged: The Bank of England left UK interest on hold at 0.5 per cent

Wall Street traded 100 points-plus down at the outset on worries about Portugal’s woes. Minutes of the Fed’s last committee meeting confirmed that ‘tapering’ will conclude in October with a final $15billion reduction in bond purchases.

The Fed was careful to avoid any inference of what this might mean for the timing of the first increase in US interest rates.

Shares of the London Stock Exchange fell 60p to 1896p on hearing that Qatar had sold a 5 per cent

stake at 1915p a pop, slashing its shareholding to 10.3 per cent and banking £260.1million in the process.

Dealers suggested Qatar could use the proceeds in acquiring stock in the forthcoming rights issue to help fund the LSE’s purchase of US indices and investment management business Russell Group.

Professional punters always get excited when Qataris raise sizeable amounts of cash, hoping it could be added to its war chest for a major acquisition.

Supermarket group J Sainsbury, up 5.7p at 314.9p, moved against the general trend on revived hopes that it could at last be added to its UK portfolio.

Qatar has retained a threatening 26 per cent stake since walking away from its £10.6billion or £6 a share bid in November 2007.

It blamed its exit on credit markets which made raising funding more expensive. It would be a good time to make a move on Sainsbury’s as chief executive Justin King this week bowed out, leaving Mike Coupe to fight off the gowing threat of foreign discounters Aldi and Lidl.

Terry Smith’s interdealer broker Tullett Prebon rose 6.7p to 249p after a court ruled in its favour in relation to a controversial hiring raid on its US businesses by rival BGC Partners in 2009.

The Financial Industry Regulatory Authority has ordered BCG to pay £19.5million to Tullett’s US subsidiaries, but also ordered the subsidiaries to pay £3.6million in compensatory damages.